This application is a continuation in part of application Ser. No. 13/405,991 which is a continuation of application Ser. No. 11/098,202, now U.S. Pat. No. 8,123,836.
Concern over air quality has triggered some developments in the area of indoor air quality improvement and/or control. Such developments have typically resulted in the production of various types of air processing systems including air filtration systems. Air filtration systems are sometimes differentiated according to air filtering capabilities and may include air filtration devices designed to be integrated within a heating, ventilation, and air conditioning (HVAC) system, or local or unitary air filtration devices. Air filtration devices configured to be integrated with HVAC systems (i.e., integrated air filtration devices) are typically capable of filtering large amounts of ambient air such as, for example, an amount of ambient air that fills a warehouse, an office building, an apartment building, a house, an entertainment hall, etc. In contrast, local or unitary air filtration devices are typically configured to filter an amount of ambient air associated with a local area such as, for example, an office, a bedroom, a bathroom, etc. The equipment described here is for use in an HVAC system.
Air filters in existing air filtration devices maybe inefficiently used because of the angle at which ambient air enters and is drawn through the air filters. In particular, in some cases only a relatively small area or space of an air filter is used effectively to trap particles while the rest of the air filter remains unused. As a result, the maintenance cost of air filtration devices may increase because air filters may be prematurely replaced and/or air flow throughput may decrease because the air filtration devices may be frequently turned off for cleaning of the air filters.